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Persistent URL http://purl.org/net/epubs/work/34725
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Record Id 34725
Title A numerical investigation of low Reynolds number gaseous slip flow at the entrance of circular and parallel plate micro-channels
Abstract Rapid progress in Micro-Electro-Mechanical Systems (MEMS) technology during the last decade has led to the development of an increasing number of micro-scale devices which involve the manipulation of fluids. An emerging issue in MEMS research, however, is the realisation that the fluid mechanics at such small scales is not necessarily the same as that experienced in the macroscopic world. For example, one of the major difficulties in predicting the transport of gases through micron-sized channels can be attributed to the fact that the continuum flow hypothesis in the Navier-Stokes equations begins to break down when the dimensions of the channel are comparable to the mean free path of the molecules. Under such conditions, the gas can no longer be regarded as being in thermodynamic equilibrium and a variety of non-continuum or rarefaction effects are likely to be exhibited. Velocity profiles, mass flow rates and boundary wall shear stresses are all influenced by the non-continuum regime. In addition, the length of the hydrodynamic development region at the entrance to a channel may also be affected. The present work forms part of a larger study into microfluidic modelling techniques and examines the role of the Reynolds number and Knudsen number on the hydrodynamic development length at the entrance to circular and parallel plate micro-channels. Numerical simulations are carried out over a range of Knudsen numbers covering the continuum and slip-flow regimes The results suggest that rarefaction has only a marginal effect on the development length in circular pipes. However, in the case of the parallel-plate geometry, entrance development lengths at the upper limit of the slip-flow regime are shown to be almost 25% longer than the corresponding continuum solution.
Organisation CCLRC , CSE , CSE-CEG
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Language English (EN)
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Paper In Conference Proceedings In ECCOMAS Computational Fluid Dynamics Conference 2001 (ECCOMAS CFD 2001), Swansea, Wales, September 2001, (2001). 2001